What Size Fume Hood Do I Need?

While designing the layout of your laboratory, you will need to plan for the placement of the fume hood. A successful laboratory layout will promote the use of laboratory space while ensuring safe working conditions for laboratory personnel. 

The fume hood size that you need will depend on factors such as the equipment you plan to use inside the hood, the type of work you will be performing, and how large your physical space is. 

The size of the room will determine whether you’ll need a 3-foot or a 12-foot hood, but the equipment you plan on using within the hood will determine whether a 5-foot or a 6-foot hood is necessary. 

Also, if your lab will be occupied by multiple people, a facility designed for intensive chemical use should have at least 2.5 linear feet of hood space per person.


National Laboratory Sales carries three-foot to fourteen-foot hoods, with every size in between. The width of the fume hood you need will be a balance between necessity and personal preference.

If you plan to have multiple people working in the hood, it should be at least 5-feet wide to allow for adequate workspace. If there will be equipment used in the hood, those dimensions should be factored in as well. Say you have a five-foot apparatus that will need to be placed inside the hood while in use, in this case, you should look at hoods that are wider than seven feet to accommodate the larger equipment. 

walk-in fume hoodbench-top fume hood


If there will be equipment enclosed in the hood, then the size of the fume hood becomes a more pertinent matter. The dimensions of the equipment will determine how deep the hood needs to be to house it. The hood must be large enough to accommodate the equipment within the prescribed safe work area of the hood, which is six inches behind the plane of the sash.

In most cases, you will be able to find a benchtop hood that will fit your needs. If the equipment is extra large and would need to be wheeled into the hood, then you’ll need a floor-mounted, or walk-in, hood.

What size fume hood blower do I need?

Some hoods are sold with blowers attached, and some aren’t. If you need to purchase a blower for your fume hood, consult with an HVAC specialist or industrial hygienist to determine what size blower is appropriate based on the size of the hood opening, length of ducting, twists and turns the ducting must make to get to the outside, type of ducting material, the diameter of ducting, and in-line filters that may be present. Because of these variables, facilities generally require an on-site consultation with a specialist to properly size a blower.

If you’re looking for the right sized fume hood, browse our selection or contact Kyle at (815) 670-6400.